Apparatus and method for charging canisters with a high pressure gas

ABSTRACT

An apparatus for charging a closed metallic canister with a gas under pressure comprising means for forming a gas filling opening in the canister, and dispensing means for sequentially injecting a high pressure gas through the gas filling opening to charge the canister, and depositing and fusing a fusible body in the gas filling opening, while continuing to inject gas into the canister and utilize the force of the gas to urge the dispensing means into sealing engagement with the canister being charged.

This application is a division of application No. 08/586,298 filed Jan.16, 1996, now U.S. Pat. No. 5,760,360.

This invention relates to a novel apparatus for charging a canister of atype used in inflatable restraining systems for vehicles with an inertgas under high pressure and then sealing such canister. This inventionfurther contemplates a novel method of injecting such gas into andsealing the canister.

BACKGROUND OF THE INVENTION

In conventional, inflatable restraining systems used in vehicles, theretypically is provided a volume of compressed gas which is released uponcollision of the vehicle to expand and thereby inflate a collapsed bagbetween the vehicle structure and a vehicle occupant. Such a compressedgas is stored in a metal canister which typically is installed in thesteering column or dashboard of the vehicle, immediately ahead of thecollapsed inflatable bag usually located at the center of the steeringwheel or on the dashboard. One of such canisters is illustrated in FIG.5 of the accompanying drawings and will been seen to include anelongated, cylindrical body section 20 merging at its ends into annularrounded portions 21 and 22 providing a pair of axially disposed endopenings. The end openings are closed by a pair of cup-shaped metallicplugs 23 and 24 usually welded to the main body section of the canister.Mounted in one of such end plugs and intended to be positioned adjacentan opening of the inflatable bag, is a propellant charge adapted todetonate and thus rupture an opening in the plug to release the storedgas within the canister. In the operation of the restraining system,upon one or more of various sensors installed at points about theperiphery of the vehicle sensing a collision condition of the vehicle,an electrical signal is generated to cause the propellant charge todetonate and thus rupture a wall section of the end plug adjacent theinflatable bag.

Upon such rupture, the stored gas in the canister releases through theruptured plug wall and inflates the bag to provide a cushioning barrierbetween the vehicle occupant and the vehicle structure. Another of suchcanisters is illustrated and described in U.S. Pat. No. 3,806,153 toJames T. Johnson.

In the manufacture of such canisters, the main body sections thereof areformed from desired lengths of tubular stock having the annular, roundedend portions thereof formed by swaging or other suitable methods. Theend plugs preferably are formed by stamping and are secured in the endopenings by welding. One of such plugs is provided with an opening forinjecting a gas under pressure into the canister. After the canistercomponents have been formed and assembled, a gas pressure sensor isinstalled in the end plug provided with the gas filling opening, thepropellant charge is installed in the opposite end plug and the canisteris filled with gas and sealed.

In filling the type of canister described with a gas under pressure, ithas been the prior practice to first insert a narrow filler tube intothe end plug of the canister provided with the gas filling opening,between the side wall of the plug and the installed sensor,communicating with the interior of the canister through the opening inthe bottom wall of the plug and engaging the bottom wall of the plugabout the periphery of the opening in the bottom wall in sealingengagement. Then, while maintaining such sealing engagement between theend of the filler tube and the bottom wall of the canister plug, a gasunder high pressure is injected through the filler tube and the plugopening into the canister, a fusible ball or bead is dispensed throughthe filler tube and deposited in the plug wall opening, a welding rod isextended through the filler tube into contact with the fusible ballseated in the plug wall opening, the welding rod is energized to fusethe ball and thus close the plug wall opening, and the welding rod andfiller tube are sequentially retracted to complete the operation.

Such process of filling inflatable bag canisters has been found to bedisadvantageous in several respects. The necessity of having to insertthe filler tube into the end plug not only requires the filler tube tobe fairly narrow in width but further requires the end plug be formedwith a sufficiently greater depth to be able to accommodate both the gasleakage sensor and the insertion of the filler tube within the confinedspace of the end plug. The increased depth requirement of the plugresults in having to machine the end plug instead of stamping it whichhas the effect of substantially increasing the cost of manufacture ofthe canister. A further disadvantage of such process is in having toposition the filler tube with the welding rod extended therethrough intoengagement with a fusible ball seated in the plug wall opening, in closeproximity to the sensor device, which generates a substantial amount ofheat which could result in damage and ultimate malfunction of thesensor. It thus has been found to be desirable to provide an apparatusand method for charging inflatable bag canisters of the type describedwith a high pressure gas in the range of 3,000 to 10,500 psi which iseffective in overcoming such disadvantages of prior art systems andmethods for charging such canisters.

Accordingly, it is the principal object of the present invention toprovide an improved apparatus for charging canisters used in inflatablerestraining systems of vehicles with a gas under high pressure.

Another object of the present invention is to provide an improvedapparatus for charging canisters used in inflatable restraining systemsof vehicles with a gas under pressure in the range of 3,000 to 10,500psi.

A further object of the present invention is to provide an improvedapparatus for charging an inflatable bag canister of a vehiclerestraining system in a manner not interfering with any propellantcharge or gas leakage sensor device typically provided on suchcanisters.

A still further object of the present invention is to provide anapparatus for charging a canister formed with a pair of cup-shaped plugsclosing openings at opposite ends of the canister accommodating apropellant charge and a gas leakage sensor, requiring comparativelyshallow plug depths, permitting such plugs to be stamped in lieu ofhaving to be machined.

Another object of the present invention is to provide an improvedapparatus for charging an inflatable bag canister used in a restrainingsystem of a vehicle which is comparatively simple in design,comparatively easy to manufacture, economical to operate and highlyeffective in performance.

A further object of the present invention is to provide a novel assemblyfor sequentially forming a seal about a gas filling opening in aninflatable bag canister used in a vehicle restraining system, injectinga gas under pressure through such opening into the canister whilemaintaining such seal, and then depositing a fusible ball in such gasfilling opening and fusing it to close the opening while continuing tomaintain such seal.

A still further object of the present invention is to provide animproved method for charging an inflatable bag canister used in avehicle inflatable restraining system with a gas under high pressure.

Other objects and advantages of the present invention will become moreapparent to those persons having ordinary skill in the art to which thepresent invention pertains from the accompanying drawings taken inconjunction with the following description.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of an embodiment of the presentinvention which provides for mounting an empty inflatable bag canisteron a retaining fixture in a selected orientation, forming a gas fillingopening in the canister, charging the canister with a gas under highpressure through the formed opening, closing and sealing the opening andthen drilling and opening to release the gas if the closure isdetermined to be defective.

FIG. 2 is a cross-sectional view taken along line 2—2 in FIG. 1,illustrating only one of the canister retaining fixtures.

FIG. 3 is an enlarged, side elevational view of one of the fixturesshown in FIGS. 1 and 2.

FIG. 4 is view taken along line 4—4 in FIG. 3.

FIG. 5 is an enlarged, side elevational view of an inflatable bagcanister adapted to be charged with a gas under pressure in theapparatus shown in FIGS. 1 and 2, illustrating the orientation in whichthe canister as retained by the fixture shown in FIGS. 3 and 4.

FIG. 6 is an enlarged, vertical cross-sectional view of a roundedshoulder portion of the canister, designated in FIG. 5.

FIGS. 6a through 6 d are views similar to the view shown in FIG. 6,illustrating sequentially the forming of a gas filling opening in therounded shoulder portion of the canister, the depositing of a fusibleball in such opening and the closure and sealing of the opening byhaving fused the ball deposited in the opening.

FIG. 7 is an end view of the fixture shown in FIGS. 3 and 4, having alower portion thereof broken away.

FIG. 8 is a side elevational view of a mechanism disposed at a canisterloading and unloading station of the apparatus shown in FIGS. 1 and 2,operable to actuate a canister retaining fixture as shown in FIGS. 3, 4and 7 to permit the loading and unloading of canisters onto and off ofthe retaining fixture.

FIG. 9 is a front elevational view of an assembly mounted at a secondstation on the apparatus shown in FIGS. 1 and 2 for forming a gasfilling opening in a canister disposed on a retainer fixture positionedat such second station.

FIG. 9a is an enlargement of the puncturing tool designated in FIG. 9.

FIG. 10 is a side elevational view of a wedging assembly positioned atthe second and third stations of the apparatus and cooperable with acanister retaining fixture also positioned at such second or thirdstation, for enhancing the retention of a canister supported on thefixture.

FIG. 11 is an enlarged view taken along line 11—11 in FIG. 10.

FIG. 12 is an enlarged, front elevational view of a gas chargingassembly positioned at a third station, of the apparatus and cooperablewith a canister mounted on a retaining fixture also positioned at suchthird station, for sequentially filling the canister with a gas underpressure through the gas filling opening formed at the second stationand then sealing such opening.

FIG. 13 is a side elevational view of the gas charging assembly shown inFIG. 12.

FIG. 14 is an enlarged, vertical cross-sectional view of the lowerportion of the gas charging assembly shown in FIG. 12.

FIG. 15 is an enlarged view of the lower portion of the gas chargingassembly shown in FIG. 13, having a portion thereof broken away.

FIG. 16 is a view similar to the view shown in FIG. 14, illustrating thelower portion of the gas charging assembly with a welding rod and gasfiller tube shown in an extended position in engagement with a canister.

FIG. 17 is an enlarged, cross-sectional view of an end portion of thefiller tube shown in FIG. 16, positioned in contact with a canister.

FIG. 18 is a cross-sectional view taken along line 18—18 in FIG. 17,having a portion thereof broken away.

FIG. 19 is a front elevational view of a drill assembly, positioned at afourth station on the apparatus and operatively engagable with acanister mounted on a retaining fixture also positioned at such fourthstation.

FIG. 20 is a top plan view of another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

Referring to the drawings, there is illustrated an embodiment of theinvention. The embodiment consists of an apparatus 30 generallyincluding a main support frame 31, a rotatable platform 32 attached to arotary indexing unit 33 seated on the main frame, a plurality ofcanister retaining fixtures 34 mounted on platform 32, spaced 90° apartthereon relative to the axis of rotation of the platform and adapted tobe cycled sequentially through first, second, third and fourth workstations relative to the main support frame, also spaced 90° apart, afixture release assembly 35 mounted on the main support frame at thefirst work station and operatively engagable with a canister retainingfixture positioned at the first work station, as best shown in FIG. 8, awedging assembly 36 mounted on the main support frame at the second workstation and operatively engagable with a canister retaining fixturepositioned at the second work station, as best shown in FIGS. 10 and 11,a hole forming assembly 37 mounted on the main support frame at thesecond work station and operatively engagable with a canister mounted ona retaining fixture positioned at the second work station, as best shownin FIGS. 1 and 9, a wedging assembly similar to wedging assembly 36mounted on the main support frame at the second work station andoperatively engagable with a canister retaining fixture also positionedat the third work station, a gas charging and sealing assembly 38mounted on the main support frame at the third work station andoperatively engagable with a canister mounted on a retainer fixture alsopositioned at the third work station, as best illustrated in FIGS. 12through 18, and a defective weld processing assembly 39 mounted on themain support frame at the fourth work station, and operatively engagablewith a canister mounted on a retaining fixture also positioned at thefourth work station, as best shown in FIG. 19.

As best shown in FIGS. 1 and 2, main support frame 31 includes asubstantially rectangularly-shaped base member, a plurality of postmembers 40 rigidly secured to and positioned at the corners of the basemember and a plurality of beam members 41 supported on and spanningpairs of adjacent post members. Indexing unit 33 is rigidly mounted onthe base member and is provided with a vertically disposed shaft towhich platform 32 is secured for rotation therewith about the verticalaxis of the shaft.

Platform 32 is supported at its radially inwardly disposed portion onthe indexing unit, and is further supported at its radially outwardlydisposed portion on a set of circumferentially spaced support members 32a. Platform 32 is adapted to be indexed through the several workstations by means of an electric motor 42 mounted on indexing unit 33and operatively connected to the shaft secured to the platform through asuitable gear reduction mechanism. Indexing motor 42 is operated by aconventional controller which further operates the other operatingcomponents of the apparatus in a sequential and coordinated manner.

Canister Retaining Fixtures

FIGS. 3, 4 and 7 best illustrate the construction of each of thecanister retaining fixtures. Each of such fixtures includes a verticallydisposed bracket 43 rigidly mounted on platform 32, in a positiondisposed radially relative to the axis of rotation of the platform.Facing inwardly and rigidly secured to support bracket 43 at an angle of39.5° is a base plate member 44. Rigidly secured to base plate member 44and spaced along the length thereof is a set of fixed block members 45,46 and 47. Disposed between fixed block members 45 and 46 and alsorigidly secured to base plate member 44 is a longitudinally disposedguide track 48. A pair of parallel guide rods 49 and 50 are journaled inaligned openings in fixed block members 45, 46 and 47, which are rigidlysecured at their outer, upper ends to a head block member 51 providedwith an inwardly and downwardly facing cam surface 52 disposed betweenthe guide rods. A displaceable abutment member 53 is rigidly secured toguide rods 49 and 50 at a point between fixed block members 45 and 46and is adapted to ride along guide track 48. Displaceable abutmentmember 53 is provided with a pair spaced openings longitudinally alignedwith the spaced openings in fixed block members 45 and 46 for receivingportions of the guide rods therethrough, to which the displaceableabutment member is secured. A canister 20 as shown in FIG. 5 is adaptedto be nested between displaceable abutment member 53 and fixed abutmentmember 47 in an operable position for forming a gas filling opening in arounded shoulder portion thereof at the second work station by means ofthe hole forming assembly, and filled with a gas through the formedopening and sealed at the third work station by the gas charging andsealing assembly.

Positioned on the fixture, the cylindrical body portion of a canister isadapted to rest on an arcuate surface 54 disposed at the bottom of arecess formed in fixed block member 46, an end portion thereof isadapted to be engaged by a concave surface 55 formed on a forwardlyprojecting section 56 of displaceable abutment member 53, and anopposite end portion thereof is adapted to be engaged by a concavesurface formed on a rearwardly projecting section 57 provided on fixedabutment member 47. A canister in the nested position as described isadapted to be yieldably retained in such position with its centerlinedisposed at the selected angle of 39.5° by means of a spring 58 woundabout a support rod 59 and interposed between a fixed base member 60 andmoveable abutment member 53. It will be appreciated that upon rearwarddisplacement of moveable abutment member 53 against the biasing actionof spring 58, a canister may be positioned either manually or bymechanical means such as by a pick-and-place type of robot, betweenmoveable and fixed abutment members 53 and 47, and upon release of therestraining force of spring 58, the moveable abutment member will becaused to ride upwardly on track 48 under the action of the spring tofirmly urge the loaded canister in position between the moveable andfixed abutment members.

The displaceable abutment member of a fixture positioned at the firstwork station may be displaced away from the fixed abutment memberthereof against the biasing action of spring 58 to permit the loadingand unloading of a canister by means of fixture release assembly 35disposed at the first station and supported on the main frame of theapparatus. Referring to FIG. 8, the assembly includes a post member 60,a crank member 61 and a pneumatic cylinder assembly 62. Post member 60is adapted to be aligned with a fixture 34 positioned at the firststation and includes a support bracket 63 disposed on a lower, outerside of the post member and a clevis 64 mounted on the upper endthereof, provided with a support pin 65. Crank 61 is pivotally mountedat an intermediate point thereof on support pin 65 and includes a roller66 on an upper arm portion thereof engagable with an outer surface 67 ofhead block member 51 of the fixture. Pneumatic cylinder assembly 62consists of a cylinder member 68 pivotally connected at a lower endthereof to support bracket 63 and a rod member 69 connected to an outerarm portion of crank 61 by means of a connecting pin 70. It will beappreciated that by supplying air under pressure to the base end ofcylinder member 68 to extend rod member 69, the crank will be pivoted tocause roller 66 to engage head block member 51 and displace abutmentmember 53 of the fixture against the biasing action of spring 58 andthus permit a canister to be loaded onto or removed from the fixturepositioned at the first station, either manually or mechanically bymeans of a robot or another mechanism.

Hole Forming Assembly

Positioned at the second station, displaced 90° from the first stationand depending from an upper beam section of the main frame is holeforming assembly 37. As best shown in FIG. 9, the assembly includes avertical, depending support structure 80, a pneumatic or hydraulic ramassembly 81 secured to and supported on structure 80 and a hole punchingunit 82 also supported on structure 80 and coupled to the ram assembly.Support structure 80 generally consists of a set of depending members 83provided with an upper cross-piece member 84 and a lower cross-piecemember 85. The ram assembly includes a vertically disposed cylindermember 86 seated at its lower end on cross-piece member 84 and engagingbase plate member 87 at its upper end, and a ram member 88 extendingthrough a vertical opening in cross-piece member 84 and having anenlarged, annular flange portion 89 at its lower end.

Hole punching unit 82 is of a conventional construction consisting of abearing 90 mounted on cross-piece member 85 and a shaft 91 verticallydisplaceable in a guide opening in bearing 90 and axially aligned withram member 88. The upper end of shaft 91 is formed with a member 92coupled to the flanged portion of ram member 88 and the lower endthereof is provided with a punching tool 93.

As best seen in FIG. 9a, tool 93 includes an upper cylindrical basesection 94 received within an opening in shaft member 91 and rigidlysecured thereto, an intermediate, cylindrical shank section 95 and alower pointed section 96. The pointed section includes an upper,inverted frusto-conically configured portion 97, an intermediate,inverted frusto-conically configured portion 98, and a lower pointed,conically configured tip section 99. Portions 97, 98 and 99 of thepunching tool which are adapted to penetrate and form an opening in arounded shoulder wall portion of a canister positioned beneath the tool,have surfaces displaced at angles relative to the centerline of the toolin progressively increasing degrees in order to provide an opening in acanister wall being pierced of a selected configuration for receivingand retaining a fusible body as later will be described. Preferably, theangles of the side walls of portions 97, 98 and 99 relative to thecenterline of the tool are in the order of 10°, 20° and 45°,respectively, so that when the tool penetrates a wall portion 21 of acanister mounted on a fixture positioned at the second work station, asshown in FIG. 6a, the tool will form an opening 100 having a convergingconfiguration, as shown in FIG. 6b, to receive and position a spherical,fusible body 101, as shown in FIG. 6c.

Hole forming assembly 36 is positioned at the second station so thatupon indexing platform 32 90° from the first station, a rounded shoulderportion 21 of a canister supported on the fixture will be verticallyaligned below punching tool 93. Upon supplying fluid under pressure tothe base end of cylinder member 86, the ram member will be displaceddownwardly a predetermined distance to cause the punching tool topenetrate and thus pierce wall portion 21 of the canister as shown inFIG. 6a to provide the opening 100 as shown in FIG. 6b.

Wedging assembly 36 is positioned at the second work station and isoperatively engagable with a fixture 34 positioned at the second stationfor enhancing the retention of the canister mounted on the fixture to bepenetrated by hole forming assembly 37. The wedging assembly is bestshown in FIGS. 10 and 11 and consists of a vertical support member 120mounted on the main frame of the apparatus and disposed in radialalignment with a fixture positioned at the second work station, and aram assembly 121 mounted on the upper end of the support member. Supportmember 120 is provided with a base plate 122 mounted on the upper endthereof which is disposed substantially perpendicular to the extendedcenterline of a canister mounted on the fixture positioned at the secondwork station. Ram assembly 121 consists of a cylinder member 123 rigidlymounted on base plate 122 and a ram member 124. A floating wedge member126 is mounted on the end of the ram member received within a recess 125therein, by means of a set of bolts extending through oversized openingsin the ram member.

Upon extension of the ram member, wedge member 126 is adapted to bereceived between spaced rod members 49 and 50 of the adjacent fixture,and an upper angled surface 126 a thereof is adapted to engage angledsurface 52 of head block member 51 in camming relation to cause blockmember 51 and correspondingly rod members 49 and 50 to further displaceupwardly to urge displaceable abutment member 53 in firmer engagementwith a canister supported thereon to enhance the retention of thecanister in the fixture for the hole forming operation.

Gas Charging and Sealing Assembly

The gas charging and sealing assembly 38 is best illustrated in FIGS. 12through 18. The assembly is positioned at the third work station,displaced approximately 90° from the second work station relative to theaxis of rotation of platform 32, and includes a support structure 130depending from the overhead section of the main frame of the apparatus,a dispensing block member 131 mounted on and depending from supportstructure 130, a sealing head assembly 132 mounted on and depending fromblock member 131 and a welding rod assembly 133 mounted on the upper endof support structure 130 and having a welding rod at a lower end thereofreceived and displaceable through aligned openings of block member 131and sealing head assembly 132.

Support structure 130 is provided with an upper base plate member 134rigidly secured to an underside of the overhead structure of the mainframe, a pair of depending members 135 and 136 secured to the base platemember and a lower mounting plate member 137. The support structure ispositioned on the overhead structure 41 so that a vertical centerlinethereof will be vertically aligned with an opening in a canistersupported on a fixture positioned at the third work station. Thecomponents of the support structure are formed of suitable steelmaterials to provide a sufficient rigidity to the entire assembly.

Block unit 131 is best illustrated in FIG. 14 and will be seen toconsist of a block of material having a peripheral flange section 138provided with suitable openings for receiving a set of bolts forsecuring the block member to lower base plate member 137, and a verticalopening 139 closed at an upper end by a plate member 140 provided with acoaxially disposed opening 141. Communicating with opening 139 is a gassupply passageway 142 and a fusible ball supply passageway 143.Passageway 142 is adapted to be connected to a system for selectivelysupplying an inert gas under pressure up to 10,500 psi to opening 139 inblock member 131. Passageway 143 is adapted to be connected to amechanism for selectively dispensing fusible balls through passageway143 and into opening 139. Such a mechanism can be of a type asillustrated and described in U.S. Pat. No. 5,196,669.

Sealing head assembly 132 consists of a set of annular plate sections144 through 147 nested and secured together and as a unit to theunderside of block member 131 by means of a set of bolts 148. The platesections as a unit provide an elongated axial bore 149 in head assembly132 longitudinally aligned and communicating with elongated bore 139 inblock member 131, having an enlarged section 150. Disposed in elongatedbore 149 and displaceable longitudinally therein is a piston member 151having a rod section 152 disposed within elongated bore 149 andprojecting outwardly therefrom, and a piston head section 153 disposedwithin enlarged bore section 150. As best shown in FIG. 14, thecylindrical side wall of piston head section 153 engages and isdisplaceable longitudinally relative to the wall surface of enlargedbore section 150, and the longitudional dimension of head section 153 isless than the longitudinal dimension of enlarged bore section 150, toprovide an upper chamber 154 and a lower chamber 155. Inner adjoiningsurfaces of annular plate sections 144, 145 and 146 are recessed and areprovided with a set of O-rings 156 and 157 forming air tight sealsbetween the adjoining plate sections and the head section of the pistonmember. Similarly, the inner surface of annular plate member 146engaging outer plate section 147 is recessed and is provided with anO-ring 158 forming an air tight seal between plate sections 146 and 147and rod section 152 of the piston member.

Annular plate sections 144 through 147 preferably are formed of anonmagnetic stainless steel material and are insulated from block member131 by an insulation spacer 132 a preferably formed of a glass phenolicmaterial.

The lower end of piston rod section 152 is provided with exteriorthreads 159 on which there is threaded a collar 160. A preloaded,helical spring 161 is disposed on the exterior portion of rod section152, interposed between end plate section 147 and collar 160. Suchspring is sized to provide 1,200 to 2,000 pounds of force to displacethe piston member downwardly into a firm sealing engagement with a wallportion 21 of a canister disposed on a fixture 34 positioned at thethird work station, with elongated axially disposed passageway 149therein communicating with an opening 100 of the canister, as shown inFIGS. 16 through 18.

Piston member 151 is maintained in a retracted, inoperative position asshown in FIGS. 14 and 15, with spring 161 in a compressed condition, bymeans of gas under pressure being supplied through a fluid passageway163 in plate section 146 and the annular clearance space between platesection 146 and rod section 152 of the piston member to lower chamber155, where it acts on the lower annular surface of head section 153 todisplace the piston member to the inoperative position, as shown in FIG.14. Upon discontinuance of the supply of gas under pressure to lowerchamber 155, it will be appreciated that the piston member, being nolonger restrained, will displace downwardly under the biasing action ofspring 161 to cause the lower end of rod section 152 to engage wallportion 21 of a canister positioned therebelow, as shown in FIG. 16.

With the piston member engaging the canister, as shown in FIGS. 16through 18, and the interior passageway of the piston membercommunicating with opening 100 in the canister, a gas under pressuresupplied through fluid passageway 142 will be caused to flow throughpassageway 139 in block member 131, the upper end of elongated bore 149in block member 132, an axially disposed passageway 162 in the pistonmember and opening 100 in canister wall 21 to pressurize the canister.As such gas under pressure is supplied to the canister, itcorrespondingly will be supplied to upper chamber 154 where it will acton the upper, annular surface of head section 153 to apply an additionalforce on the piston member, enhancing the force applied by spring 161and thereby urging the end of the rod section of the piston member intogreater sealing engagement with the canister being charged. After thecanister has thus been charged to the desired pressure, the assembly isoperable to dispense a fusible ball 101 through passageway 143,passageway 139, passageway 149 in assembly 132 and axial passageway 162in the piston member, into opening 100 in the canister where it becomesseated as shown in FIG. 6c, while continuing to maintain the lower endof the piston member in firm sealing engagement with the canister andcontinuing to supply gas under pressure in the assembly. Under suchconditions, welding rod assembly 133 may be operated to fuse the fusibleball seated in opening 100 of the canister to close and seal thecanister charged with a gas in the range of 3,000 to 10,500 psi.

Elongated bore 162 in the piston member is provided with a liner 164formed of an insulating material, preferably a glass phenolic material.The upper end of the liner is formed with an annular lip portion 165which slightly overlaps the upper surface of piston head section 153,and is adapted to be received within an upper portion of elongated bore149, in contact with an annular shoulder thereof to restrict the upwarddisplacement of the piston member. The upper end of the cylindrical bore149 is provided with a bushing 166, also formed of an insulatingmaterial, having an outwardly flared lip portion at the upper endthereof disposed between a portion of guide block 144 extending into anenlarged lower section of elongated bore 139 and an annular shoulder ofsuch enlarged section.

Welding rod assembly 133 is best shown in FIG. 12 and is disposed invertical alignment with piston member 151. The assembly includes an aircylinder assembly 167 providing a cylinder member 168 and a piston rodmember 169. An electrical insulating member 170 is mounted on the lowerfree end of rod member 169, on which there is supported a couplingassembly 171. The coupling assembly includes an upper, invertedcup-shaped housing member 172, a lower housing member 173 threaded intothe lower open end of housing member 172, a plunger member 174 having aspring seating upper head portion disposed within upper housing member172 and a lower rod portion projecting through lower housing member 173,and a coil spring disposed in upper housing member 172 between the upperhousing member and the spring seating head portion of plunger 174.Plunger 174 further includes a depending coupling member 175 to which awelding rod 176 is attached, provided with a terminal member 177.

The welding rod is disposed in vertical alignment with piston member 151and is adapted to be received within elongated bore 139 in block member131 and elongated bore 162 in piston member 151, and be displacedtherein between an upper, retracted inoperative position as shown inFIG. 14 clear of passageways 142 and 143 in block member 131, and alower, extended operative position in contact with a fusible body 101seated in an opening 100 in a wall portion 21 of a canister retained ona fixture positioned at the third work station, by means of air cylinderassembly 167. The lower end of the welding rod is formed with a suitablyrecessed configuration so as to provide a good mechanical and electricalcontact with a fusible body seated in a gas filling opening of thecanister. Excessive downward pressure by the air cylinder is avoided bythe displacement of the welding rod relative to rod member 169 permittedby the cushioning spring disposed in coupling assembly 171.

To prevent the leakage of charging gas from elongated bore 139 in blockmember 131, a suitable seal is provided between retaining plate member140 and the portion of welding rod 176 passing through opening 141 inthe plate member.

Rigidly secured to the lower end of support structure 130 and spaced180° apart relative to the centerline of the welding rod assembly is apair of downwardly converging brackets 180 and 181. Secured to suchbrackets is a pair of downwardly converging, tubular guide members 182and 183 having centerlines intersecting each other and the verticalcenterline of the welding rod assembly at a point below piston member151. Mounted on brackets 180 and 181 is a pair of identical air cylinderassemblies 184 and 185. Cylinder assembly 184 includes a cylinder member186 having a mounting bracket 187 seated on and secured to bracket 180,and a piston rod member 188 extending through and displaceable axiallyin tubular guide member 182. The lower free end of rod member 188 isprovided with an electrode 189 provided with a terminal member 190,insulated from rod member 188 by an insulation member 191. Similarly,air cylinder assembly 185 includes a cylinder member 192 having amounting bracket 193 seated on and secured to bracket 181 by means of aset of bolts, and a piston rod member 194 extending through and axiallydisplaceable within tubular guide member 183. An electrode 195 isprovided on the lower free end of rod member 194, having a terminalmember 196 insulated from rod member 194 by means of an insulationmember 197.

Terminal members 190 and 196 of electrodes 189 and 195 are connected toa secondary lead of a welding transformer, and terminal member 177 ofwelding rod 165 is connected to the other secondary lead of thetransformer. When a canister is positioned at the third work stationwith a gas filling opening 100 vertically aligned with the welding rodassembly, a fusible body 100 is nested in the gas filling opening, thepiston member is extended to engage the canister and form an air tightseal about the gas filling hole and the welding rod is extended toengage the fusible body seated in the gas filling opening as shown inFIG. 16, rod members 188 and 194 of assemblies 184 and 185 are adaptedto be extended to cause electrodes 189 and 195 to engage the canister.Upon a suitable set of contacts being closed to complete the secondarycircuit of the welding transformer, an electrical current of highamperage in the order of 2,000 amps for a short duration of time in theorder of a fraction of a second will be applied to fuse the fusible bodyseated in the gas filling hole of the canister to close and seal thecanister.

FIGS. 14 and 15 illustrate the gas charging and sealing assembly in aninoperative condition. In such condition, no gas under pressure isapplied through passageway 142 to upper gas chamber 154, and gas underpressure is supplied to passageway 163 in the head assembly to lower gaschamber 155 to displace piston member 151 to an upper position againstthe biasing action of spring 161. Air pressure is supplied to the rodend of cylinder member 168 to retract welding rod 176 to an upperposition above the level of passageways 142 and 143 in block member 131,and air pressure is supplied to the rod ends of cylinder members 186 and192 to position electrodes 189 and 195 in retracted positions. Inaddition, a set of contacts in the secondary circuit of the weldingtransformer are disposed in an open condition.

When the indexing mechanism of the apparatus advances a fixture to thethird work station so that a gas filling opening 100 of a canister ispositioned in vertical alignment with the welding rod assembly, andsuitable controls are operated, the supply of gas under pressure tolower gas chamber 155 is discontinued to allow spring 161 to extendpiston member 151 into engagement with the canister, with longitudinalbore 162 communicating with gas filling opening 100 in the canister andthe tip portion of the piston rod section about the periphery of thelower open end of bore 162 engaging the canister about the periphery ofopening 100, in sealing arrangement. Gas under pressure is then suppliedthrough passageways 142 and 139 and the passageways in the head assemblyand piston member to charge the cylinder under a pressure in the rangeof 3,000 to 10,500 psi. As such gas is supplied to the canister, itfurther will be supplied to upper gas chamber 154 where it acts upon thepiston member to enhance the sealing force applied to the piston byspring 161 thus assuring a firm sealing engagement of the piston memberwith the canister.

After a predetermined interval sufficient to charge the canister at theselected charging pressure and enhance the sealing engagement of thepiston with the canister, and while maintaining the supply of gas underpressure, a fusible ball is dispensed through passageway 143 and thepiston member to become nested in the gas filling opening of thecanister. Then, while continuing to maintain the seal between the pistonmember and the canister and maintaining the assembly under pressure,further controls are operated to sequentially extend rod members 188 and194 so that electrodes 189 and 195 engage the canister and provide goodelectrical contacts, welding rod 176 is extended into mechanical andelectrical contact with the fusible ball seated in the gas fillingopening, and appropriate contacts in the secondary transformer circuitare closed to provide current in the secondary transformer circuitsufficient to cause the fusible body to fuse and close the opening inthe canister, sealing the pressurized canister.

After a further interval of time sufficient to allow the closure to cooland solidify, appropriate controls are operated to retract electrodes189 and 195 out of contact with the canister, welding rod 176 isretracted to the position shown in FIG. 14, the supply of gas topassageway 142 is discontinued, allowing gas in upper chamber 154 to bevented, and gas under pressure again is supplied to lower gas chamber155 to cause the piston member to retract upwardly out of sealingengagement with the canister against the action of spring 161. The gascharging and sealing assembly is then in condition to begin anothercycle of filling and sealing the next canister to be advanced to thethird work station.

Although the gas filling and sealing assembly shown in FIGS. 12 through16 provides for dispensing a fusible body from a storage position withinthe assembly, it further is contemplated within the scope of the presentinvention to supply such fusible body from a storage position exteriorof the assembly. In such alternate embodiment, it is contemplated that amechanism would transfer the fusible body from an exterior storageposition to a position below and vertically aligned with the weldingrod, and that the assembly would operate to extend the welding rod downthrough the piston member to engage and attach the body and retract intothe position shown in FIG. 14. In such an arrangement, the fusible bodywould be attached to the welding rod by a vacuum applied to an axialpassageway in the welding rod or by any other suitable means.

In the inoperative condition of the alternate embodiment, assembly 38would be in a condition essentially as shown in FIGS. 14 and 15 with thepiston member, the welding rod and the electrodes 189 and 195 in theirretracted positions. Upon operation of the assembly, suitable controlswould be operated to first actuate a transfer mechanism to position afusible body below the piston member in vertical alignment with thewelding rod. With the fusible body thus positioned, further controlswould be operated to extend the welding rod down into engagement withthe fusible body, a negative pressure would be applied to the passagewayin the welding rod to detachably secure the fusible body to the lowerend of the welding rod and then the welding rod would be retracted tothe position shown in FIG. 14. Thereafter, the assembly operates in themanner described in the previously described embodiment to charge thecanister, position the fusible body in a gas filling opening in thecanister, engage the welding rod and electrodes and then energize thesecondary circuit of the welding transformer to fuse and close the gasfilling opening in the canister.

To assure the firm retention of the canister being charged and sealed atthe third work station, a wedging assembly similar to wedging assembly36 is positioned at the third work station of the apparatus which isoperatively engagable with the fixture positioned at the third workstation in the manner previously described for drawing the fixedabutment member of such fixture more firmly into engagement with thecanister to assure its retention on the fixture in proper orientation toposition the gas filling opening therein in vertical alignment with thepiston member and welding rod of the gas charging and sealing assembly.

Defective Canister Processing Assembly

Located at the third or fourth work station or at a position betweensuch stations is a device for detecting a defective weld in a canisterhaving been charged and sealed at the third work station. Such a devicemay consist of a gas leakage detector which is operable to indicate anunsatisfactory closure in a canister advanced from the third workstation. Upon detection of such a defective closure in a canister bysuch a detection device, the assembly shown in FIG. 19, situated at thefourth work station of the apparatus, is operated to form an opening forreleasing the gas in the defective canister charged at the third workstation upon the positioning of the canister at the fourth work station.Assembly 39 includes a support structure 200, a cylinder assembly 201and a drill unit 202. The support structure may be either mounted on themain support frame or independent thereof but adjacent the fourth workstation. Cylinder assembly 201 may be positioned at any convenient angleand includes a cylinder member 203 supported on a bracket 204. Drillunit 202 is displaceable along the axis of cylinder member 203,intersecting the side wall of a canister supported on a fixturepositioned at the fourth work station. It further is provided with adrill bit 205 adapted to engage and drill a hole in the side wall of thecanister.

Upon detection of a defective closure in a canister advanced from thethird work station, and the positioning of the canister at the fourthwork station, suitable controls are operated to operate drill unit 202and to supply fluid under pressure to the base end of cylinder member203 to displace the drill bit to drill a relief hole in the side wall ofthe canister and allow the gas therein to be released. Upon release ofthe gas in the canister, the canister may be removed and scrapped orotherwise discarded.

In the event the defective weld detecting device fails to detect adefective closure of a canister advancing from the third work station,assembly 39 will not be activated and the fixture supporting thecanister will be advanced past the fourth work station to the first workstation where it is unloaded from the apparatus.

Operation

A conventional programmable controller functions to operate theapparatus as described. In particular, the controller functions tooperate indexing mechanism 42 to advance support platform 31 in 90°increments and sequentially position a fixture 34 at each of the workstations, actuate assembly 37 to form a gas filling opening in acanister supported on a fixture positioned at the second work station,actuate the gas charging and sealing assembly to charge and seal acanister supported on a fixture positioned at the third work station,selectively actuate the weld removal assembly to remove a defectiveclosure in a canister supported on a fixture positioned at the fourthwork station and to return a canister to the first work station forremoval if satisfactorily charged and sealed, or recycling if theclosure has been detected to be defective and has been removed.

In a typical cycle of the apparatus as described, the controller firstoperates a suitable valve to supply fluid under pressure to the base endof cylinder member 68 of fixture release assembly 35 to extend rodmember 69 and pivot crank 61 in a clockwise direction relative to FIG.8. The pivotal movement of crank 61 will cause roller 66 to engage anddisplace block member 51 of a fixture positioned at the first station ofthe apparatus. The displacement of block 51 will cause moveable abutmentmember 53 of the fixture to be displaced apart from fixed abutmentmember 47 of the fixture against the biasing action of coil spring 59 ofthe fixture. A canister of the type shown in FIG. 5 then may be loadedonto the fixture and seated on support surface 54. The canister may beloaded onto the fixture either manually or mechanically such as with theuse of a pick-and-place type of robot which also may be operated by thecontroller or otherwise coordinated with the operation of the apparatus.Upon placement of the canister in the fixture between the fixed andmoveable abutment members, the controller will function to operate thecontrol valve for cylinder member 68 to remove fluid under pressure fromthe base end thereof and allow the moveable abutment member of thefixture to displace towards the fixed abutment member under the actionof coil spring 59 to firmly clamp the canister in position with thecenterline thereof disposed at an angle of 39.5°.

Once the canister is firmly retained on the fixture positioned at thefirst work station, the controller functions to operate the indexingmechanism to rotate platform 32 to advance and position the fixture atthe second work station. Sensing the fixture being positioned at thesecond work station, the controller functions to operate a suitablevalve to supply fluid under pressure to the base end of cylinder member123 of wedging assembly 36 to extend the rod member thereof and causewedge member 126 to engage cam surface 52 of block member 51 of thefixture. The camming action of the wedge member functions to enhance theclamping action of the moveable abutment member of the fixture therebyenhancing the retention of the canister in the fixture for the piercingoperation to follow.

Sequentially, the controller functions to operate a certain valve tosupply fluid under pressure to the base end of cylinder member 86 of thehole piercing assembly causing rod member 88 to displace downwardly andcorrespondingly cause piercing tool 93 to form an opening 100 in arounded shoulder portion 21 of the canister supported on the fixture.The stroke of rod member 88 is designed to cause the piercing tool topierce the canister wall in the manner as shown in FIG. 6a to provide anopening 100 with a converging side wall adapted to receive and nest aspherical fusible body 101 as shown in FIG. 6c. Upon formation of theopening in the canister wall, the controller functions to operatesuitable valves to retract rod member 88 of assembly 36 and rod member124 of wedging assembly 36 to free the fixture holding the piercedcontainer.

The disengagement of the hole forming and wedging assemblies at thesecond work station functions to operate the indexing mechanism to againrotate platform 32 90° to advance and next position the fixture at thethird work station. Upon sensing the fixture positioned at the thirdwork station, the controller functions to sequentially operate a valveto remove the supply of fluid under pressure to passageway 163 and lowergas chamber 155 of the welding head assembly thus permitting pistonmember 151 to be displaced downwardly under the action of coil spring161 into engagement with the rounded shoulder portion of the canisterdisposed therebelow, and then operate a second valve to supply the gasto be charged into of the canister to passageway 142 and simultaneouslythrough elongated bore 162 of the piston member to charge the canisterthrough gas filling opening 100, and chamber 154 to provide anadditional force on the piston member which functions to enhance thesealing engagement of the rod portion of the piston member with thecanister. The canister is first supplied with gas at a selected highpressure to test the structural integrity of the canister. If nostructural defect is detected, the pressure of the gas is reduced to aselected lower pressure at which the canister is to be pressurized. If astructural failure is detected, suitable controls will be operated todiscontinue the gas supply and allow removal of the defective canisterat a selected location in the cycle. Assuming the canister is testedpositively, a mechanism within assembly 38 then operates to dispense aspherical fusible ball through passageway 143 and elongated bore 162 toopening 100, as shown in FIG. 6c, as the charging gas continues to besupplied to the canister. With the fusible body thus nested in the gasfilling opening of the canister and the charging gas pressure beingmaintained, the controller functions to operate suitable valves tosupply air under pressure to the base ends of cylinder members 186 and192 to extend the rod members thereof and cause electrodes 189 and 195to engage the canister in firm mechanical and electrical contact. Thewelding rod assembly is then operated to extend welding rod 176downwardly through elongated bore 162 of the piston member to engage thefusible body, as shown in FIG. 16, while continuing to supply thecharging gas to the welding head assembly. Upon engagement of thewelding rod with the fusible body, the controller functions to closesuitable contacts in the secondary circuit of the welding transformer tosupply a low voltage, high amperage current of a suitable magnitude andfor a duration of time sufficient to fuse the fusible body, causing itto close and seal the gas filling opening in the canister as shown inFIG. 6d. The controlled downward stroke of the weld rod assembly and theyielding effect provided by the spring disposed in housing 171 permitsthe lower end of the welding rod to provide a suitable mechanical andelectrical contact with the fusible ball member with an appropriateamount of pressure to form the desired closure and seal in the gasfilling opening in the canister.

The stroke of piercing tool 93 and the configuration of end portion 96thereof provides a configuration of gas filling hole 100 whichfacilitates the positioning of a fusible ball therein as shown in FIG.6c, positive engagement of the lower end of the welding rod with thefusible ball, in good mechanical and electrical contact therewith, thedesired flow of molten ball material to sufficiently close the openingand suitable heat transfer for solidifying the molten material into astructurally integral, fluid tight closure. The converging profile ofthe hole provides a large enough opening to inject gas into the canisteryet small enough to receive and nest a fusible ball at the upper endthereof as shown in FIGS. 6b and 6 c. The volume of the ball is sized sothat upon fusing the ball, the molten material will sufficiently fillthe hole space as shown in FIG. 6d.

Upon the passage of a suitable interval of time, allowing the closure tosolidify and properly seal the opening, the controller functions tosequentially retract the welding rod assembly, retract electrodes 189and 195, discontinue the supply of charging gas to passageway 142 andthen supply gas under pressure to passageway 163 and correspondinglylower gas chamber 155 of the welding head assembly to cause pistonmember 151 to retract out of engagement with the canister, against thebiasing action of coil spring 161. The wedging member located at thethird work station and operatively engagable with the fixture forenhancing the retention of the canister during the gas charging andsealing operation is then disengaged to free the fixture for advancementto the next work station.

The defective closure detection device then functions to determinewhether the closure and seal of the gas filling opening of the canisteris satisfactory or unsatisfactory. If a satisfactory condition issensed, the controller will function to operate the indexing mechanismto advance the fixture past the fourth work station to the first workstation where the release assembly is again actuated to permit theunloading of the satisfactorily pressurized and sealed canister and theloading of a new canister to be cycled as described. If anunsatisfactory closure and seal is sensed, the controller will functionto advance the fixture to the fourth station and actuate the removalassembly to drill a relief hole in the side wall of the canister,allowing the residual gas in the canister to be released. Upon releaseof the gas from the canister and the removal of the canister from thefixture, the indexing mechanism is operated to advance the fixture tothe first station where another canister to be charged may be mounted onthe fixture to start another cycle.

In the procedure as described, when the canister with the pierced gasfilling hole is positioned at the third work station to be charged andsealed, the structual integrity of the canister may be tested by firstapplying the charging gas under an elevated pressure in the range of8,500 to 10,500 psi and then if the canister is determined to bestructurally sound, the charging gas pressure may be reduced to anoperating pressure of the gas in the canister in the range of 3,000 to5,400 psi.

In circumstances where the piercing of the canister at the second workstation may result in undue stress concentrations in the wall portion ofthe canister in the vicinity of the pierced opening, possibly resultingin subsequent structural failure of the canister, such an occurrence maybe avoided by utilizing a drilling operation instead of a punchingoperation at the second work station. In essence, a drilling assemblycomparable to assembly 39 would be substituted for the hole punchingassembly 37 at the second work station. Alternatively, the work stationsmay be arranged to provide a first loading and unloading station, asecond work station provided with a drill assembly which operates toselectively form a partial or complete drilling of a wall portion of thecanister, a third station provided with a puncturing assembly forpunching a hole completely through a partially drilled hole and a fourthstation provided with a gas charging and sealing assembly of the typedescribed. In such an arrangement, the canister would be loaded at thefirst station, a hole would be partially drilled at the second station,the partially drilled hole would be completely punched through thecanister wall at the third station, the canister would be chargedthrough the partially drilled and completely punched through hole andthen sealed at the fourth work station and the canister would then bereturned to the first work station. If such canister was detected ashaving a satisfactory seal, it then would be unloaded at the firststation and a new canister would be loaded onto the fixture to be cycledas described. If an unsatisfactory canister was detected, the controllerwould operate to advance the fixture with the defective canister to asuitable station provided with an assembly comparable to assembly 39 todrill a relief hole to discharge the gas from the canister and thendispose of the depleted canister.

FIG. 20 illustrates another embodiment of the invention in whichcanisters are advanced along a linear line of travel to a number of workstations at which various work functions are performed. The embodimentconsists of an apparatus 300 including a main support frame 301, aconveyor 302 mounted on the support frame, a plurality of pallets 303spaced along the conveyor and means for operating the conveyor toadvance the pallets intermittently along the line of work stations. Eachof the pallets is provided with a fixture similar or comparable tofixture 34 described in connection with the embodiment shown in FIGS. 1through 4 for releasibly retaining a canister in a selected orientationto be pierced, filled with a gas under pressure and sealed as in thepreviously described embodiments.

Referring to FIG. 20, the apparatus will be seen to provide a canisterloading station A, a piercing station B, a pre-weighing station C, a gascharging and sealing station D, a post-weighing and defective weldprocessing station E and an unloading station F. Mounted on main frame301 at station B is a hole piercing assembly comparable to the holepiercing assembly shown in FIGS. 9 and 9a. Such assembly is positionedon the main frame relative to conveyor 302 so that when a palletcarrying a canister disposed in a selected orientation, is positioned atstation B , the piercing tool of the assembly will be vertically alignedwith the portion of the canister to be punctured. Mounted on main frame301 at station C is a transfer mechanism 304 which is adapted tolaterally displace a pallet 301 positioned at station C, weigh theempty, pierced canister and transfer it laterally back onto the conveyorfor advancement to station D. A gas charging and hole sealing assemblycomparable to the assembly shown in FIGS. 12 through 18 is mounted onmain frame 301 at station D which functions to charge a canistersupported on a pallet positioned at station D with a gas under pressure,and seal the gas filling hole in the canister in the manner aspreviously described.

Disposed between stations D and E or at station E is a means fordetecting a defective closure weld as in the previously describedembodiment. Also mounted on the main frame at station E is a mechanismfor post weighing a filled and sealed canister positioned at station E,and a defective weld processing assembly comparable to the assemblyshown in FIG. 19. Upon detection of a defective closure weld or anunderweight or overweight canister positioned at station E, thedefective weld processing assembly will be operated to drill a reliefhole in the canister and allow the release of gas from the canister. Thepallets supporting canisters at station E are then transferred laterallyby a mechanism 305 from where they are advanced to station F forunloading.

Preferably, conveyor 302 is an endless conveyer on which pallets 301 arespaced apart the distances between successive stations on the apparatus.Canisters loaded onto fixtures supported on pallets at station A areincrementally advanced by the conveyor sequentially to station B wherethe gas filling hole is formed, station C where the canister ispre-weighed, station D where the canister is charged with a gas underpressure and the gas filling hole in the canister is sealed with a weldclosure, station E where the canister is post-weighed and the closureweld of any defective canister is removed and station F where thecanister is removed either to undergo further processing or to berecycled.

Although the canister has been described as being oriented at an angleof 39.5° relative to the horizontal, and the gas filling hole positionhas been described as being located at a rounded shoulder portion of thecanister, in connection with the embodiment shown in FIGS. 1 through 19,it is contemplated that the canister can be oriented in any position andthe gas filling hole may be located at any area of the canisterincluding the end portions, the rounded shoulder portions or thecylindrical main body portion thereof. It further is contemplated withinthe scope of the present invention that the embodiment described inconnection with FIG. 20 may include means disposed at station B forforming the gas filling opening in the canister by drilling or partiallydrilling and puncturing as described in the modification of theembodiment shown in FIGS. 1 through 19.

From the foregoing detailed description, it will be evident that thereare a number of changes, adaptations and modifications of the presentinvention which come within the province of those persons havingordinary skill in the art to which the aforementioned inventionpertains. However, it is intended that all such variations not departingfrom the spirit of the invention be considered as within the scopethereof as limited solely by the appended claims.

What is claimed is:
 1. An apparatus for charging a closed metalliccanister with a gas under pressure comprising: support means having afirst canister loading an unloading station and second and thirdstations; at least one means disposed on said support means forremovably retaining said canister in a predetermined orientation; secondmeans for advancing said canister retaining means sequentially to saidstations; third means disposed at said second station for forming anopening in a wall portion of said canister positioned in said secondstation; and fourth means disposed at said third station forsequentially injecting said gas under pressure through said opening intosaid canister positioned at said third station, and then depositing andfusing a fusible body in said openingto close said opening whilemaintaining said gas injected into said canister under pressure,including means utilizing the force exerted by said gas under pressurefor urging a contact portion of said fourth means into sealingengagement with said canister during the gas injecting, fusible bodydepositing and fusible body fusing, in closing said gas filling opening.2. An apparatus according to claim 1 wherein said retaining meansincludes means for positioning a rounded shoulder wall portion of saidcanister in a predetermined position for forming said opening thereinwhen said canister is positioned at said second station.
 3. An apparatusaccording to claim 2 wherein said retaining means includes means forsupporting said canister in an orientation with a longitudinalcenterline thereof disposed at an acute angle relative to thehorizontal.
 4. An apparatus according to claim 3 wherein said angle is39.5°.
 5. An apparatus according to claim 1 wherein said retaining meansincludes releasable means for clamping said canister in saidpredetermined orientation.
 6. An apparatus according to claim 5including means for disabling said clamping means to permit loading andunloading of said canister onto and off of said retaining means whensaid canister is positioned at said first station.
 7. An apparatusaccording to claim 5 wherein said clamping means includes means forexerting a yieldable biasing force on said canister when disposed onsaid retaining means for retaining said canister in said predeterminedorientation.
 8. An apparatus according to claim 7 including means forexerting a force opposing said biasing force to permit loading andunloading of said canister onto and off of said retaining means.
 9. Anapparatus according to claim 1 wherein said opening forming meansincludes a displaceable wall piercing tool.
 10. An apparatus accordingto claim 9 wherein said piercing tool is provided with a canister wallpenetrating portion having a configuration for forming a wall opening insaid canister with a configuration for receiving and retaining saidfusible body therein.
 11. An apparatus according to claim 9 includingfluid actuated means operable upon positioning of said canister at saidsecond station for displacing said wall piercing tool to form saidopening in said canister wall portion.
 12. An apparatus according toclaim 9 including means disposed at said second station operativelyengagable with said retaining means for enhancing the retention of saidcanister in said predetermined orientation when said cannister ispositioned at said second station.
 13. An apparatus according to claim 1wherein said fourth means comprises: dispensing means engagable insealing relation with said canister disposed on said retaining meanspositioned at said third station, communicating a passageway thereinwith an opening in said cannister formed at said second station; meansfor supplying a gas under pressure to said passageway to pressurize saidcannister while maintaining said sealing engagement; means fordelivering said fusible body through said passageway to said cannisteropening while maintaining said sealing engagement and continuing tosupply gas under pressure to said passageway; and means insertablethrough said passageway for fusing said fusible body disposed in saidcanister opening while maintaining said sealing engagement andcontinuing to supply gas under pressure to said passageway, to seal saidcanister opening.
 14. An apparatus according to claim 13 includingretractable biasing means for urging said dispensing means in sealingengagement with said canister.
 15. An apparatus according to claim 13including means for applying gas under pressure for urging saiddispensing means in sealing engagement with said canister.
 16. Anapparatus according to claim 13 including means for applying amechanical spring force and the force of a fluid under pressure forurging said dispensing means into sealing engagement with said canister.17. An apparatus according to claim 13 including means for introducingsaid fusible body into said passageway at a location disposed upstreamof an outlet port thereof communicable with said canister opening aftersaid dispensing means has been disposed in sealing engagement with saidcanister.
 18. An apparatus according to claim 13 including means forintroducing said fusible body into said passageway through an outletport thereof communicable with said canister opening prior to saiddispensing means being positioned in sealing engagement with saidcanister.
 19. An apparatus according to claim 18 including meansdisposed in said passageway and extendable through said outlet port fortransferring said fusible body from outside to within said passageway.20. An apparatus according to claim 19 wherein said extendable meansincludes means detachably securing said fusible body thereon by vacuummeans.
 21. An apparatus according to claim 19 wherein said extendablemeans comprises said fusing means provided with a passagewaycommunicable with said fusible body and connected to a vacuum source.22. An apparatus according to claim 13 including means disposed at saidthird station operatively engagable with said retaining means forenhancing the retention of said canister in said predeterminedorientation when said canister is positioned at said third station. 23.An apparatus according to claim 1 wherein said support means includes afourth station, and said advancing means is operable to advance saidcanister retaining means from said third station to said fourth station,and including means disposed at said fourth station for selectivelyforming a relief opening in a canister supported on said retainer meansand positioned at said fourth station for releasing said gas having beeninjected therein.
 24. An apparatus according to claim 23 wherein saidrelief opening forming means is operable upon a determination of adefective condition of a fusible body sealing said first mentionedopening.
 25. An apparatus according to claim 23 including means fordetecting a predetermined defective condition of a fused body disposedin said first mentioned opening in said canister supported on saidretaining means positioned at said fourth station, and wherein saidrelief opening forming means is operable responsive to a saiddetermination of said predetermined defective condition by saiddetecting means.
 26. An apparatus according to claim 23 wherein saidrelief opening forming means comprises a drill assembly.
 27. Anapparatus according to claim 26 wherein said drill assembly is supportedon said support means and includes a drill bit displaceable along a lineof travel aligned with a canister supported in said predeterminedposition on said retaining means positioned at said fourth station. 28.An apparatus according to claim 1 wherein said support means includes amain frame and a platform disposed on said main frame and rotatableabout a vertical axis, said retaining means is supported on saidplatform and said advancing means is operable to rotate said platformand thereby sequentially position said retaining means at said first,second and third stations.
 29. An apparatus according to claim 28wherein the sequential advancement of said platform is coordinated withthe operations of said opening forming means and said gas injecting andfused body depositing and fusing means.
 30. An apparatus according toclaim 23 wherein said support includes a main frame and a platformdisposed on said main frame and rotatable about a vertical axis, saidretaining means is supported on said platform and said advancing meansis operable to rotate said platform and thereby sequentially positionsaid retaining means at said first, second, third and fourth stations.31. An apparatus according to claim 30 wherein the sequentialadvancement of said platform is coordinated with the operations of saidopening forming means, said gas injecting and fused body depositing andfusing means and said relief opening forming means.
 32. An apparatusaccording to claim 23 including means disposed at said fourth stationoperatively engagable with said retaining means positioned at said forthstation for enhancing the retention of said canister in saidpredetermined orientation.
 33. An apparatus for charging a closedmetallic canister having a cylindrical body portion and a roundedshoulder portion with a gas under pressure comprising: support meanshaving a first canister loading and unloading station and second andthird stations; at least one means for removable retaining said canisterin a predetermined orientation; means for advancing said canisterretaining means sequentially to said stations; means disposed at saidsecond station for forming an opening in said rounded wall portion ofsaid canister positioned at said second station including a piercingtool displaceable along a line of travel penetrating said rounded wallportion, said piercing tool having an end configuration and length ofpenetrating said rounded wall portion, said piercing tool having an endconfiguration and length of penetrating stroke to form an opening havingdiverging configuration providing a lower annular support surface forreceiving and returning a fusible body; and means disposed at said thirdstation for sequentially injecting said gas under pressure through saidopening into said canister positioned at said third station, and thedepositing and fusing a fusible body in said opening to close saidopening while maintaining said gas injected into said canister underpressure, including means utilizing the force exerted by said gas underpressure for urging a contract portion of said fourth mentioned meansinto sealing engagement with said canister during the gas injecting,fusible body depositing and fusible body fusing, in closing said gasfilling opening.
 34. An apparatus according to claim 33 including meansdisposed at said second station operatively engagable with saidretaining means positioned at said second station for enhancing theretention of said canister in said predetermination orientation.
 35. Anapparatus according to claim 33 wherein said means for forming saidopening includes fluid actuated means for displacing said piercing toolto provide said opening.
 36. An apparatus according to claim 33 whereina wall penetrating end portion of said piercing tool includes first,second and third sections with side walls disposed in progressivelygreater angular displacements relative to a centerline thereof.
 37. Anapparatus according to claim 36 wherein said piercing tool sections areconically configured and angularly displaced 10°, 20° and 45°,respectively, relative to the centerline of said tool.
 38. An apparatusfor charging a closed metallic canister with a gas under pressurecomprising: support means; means disposed on said support means forremovably retaining said canister in a predetermined orientation; firstmeans for advancing said canister retaining means, along a predeterminedline of travel sequentially to at least two work stations; second meansdisposed at a first work station for forming a gas filling opening in acanister disposed on a retaining means located at said first workstation and; third means disposed at a second work station operable tosequentially inject a gas under pressure into a canister disposed on aretaining means located at said second work station, through said gasfilling opening, and then depositing and fusing a fusible body in saidgas filling opening to close said opening while maintaining gas chargedinto said canister under pressure, including means utilizing the forceexerted by said gas under pressure for urging a contact portion of saidthird means into sealing engagement with said canister during the gasinjecting, fusible body depositing and fusible body fusing in closingsaid gas filling opening.
 39. An apparatus according to claim 38including means disposed at a work station located between said firstand second work stations along said line of travel for pre-weighing acanister provided with a gas filling opening, and means disposed at awork station located after said second work station for post-weighing apressurized canister having a closed and sealed gas filling opening. 40.An apparatus according to claim 38 wherein said means for injecting agas under pressure into said canister and then depositing a fusible bodyin said gas filling opening, includes a member with a passageway,engagable with a canister about the periphery of said gas fillingopening therein, with the passageway thereof communicating with said gasfilling opening, and means for supplying a gas under pressure throughsaid passageway of said member and said gas filling opening of saidcanister to charge said canister, and against a surface of said memberto produce a force causing said member to engage said canister insealing engagement.
 41. An apparatus for charging a gas under pressureinto a metallic canister through a gas filling opening formed in a wallportion thereof and sealing said opening comprising: a member having apassageway therethrough, engageable with said canister wall portionabout said gas filling opening therein, with the passageway thereofcommunicating with said gas filling opening; means for supplying a gasunder pressure through said passageway of said member and said gasfilling opening in said canister wall portion, and against a surface ofsaid member to produce a force urging said member into sealingengagement with said canister wall portion about the periphery of saidgas filling opening; means for dispensing a fusible ball through saidpassageway of said member to nest in said gas filling opening in saidcanister wall portion while continuing the supply of said gas underpressure; and means for extending a welding rod through said passagewayof said member into engagement with said fusible ball nested in said gasfilling opening in said canister wall portion while continuing to supplysaid gas under pressure through said passageway of said member andagainst said member to maintain said member in sealing engagement withsaid canister wall portion about said gas filling opening.